Mincard:MaxCard Notation (1)
What is the meaning of 0:M or [0..M]?
- The two symbols 0 and M are called the minmum and maximum cardinality, respectively, of the corresponding role in the relation.
- I call this the MinCard:MaxCard notation - RJL
- MinCard is called Optionality in many older notations.
Traditional notations denote MaxCard pairs and Optionality in different ways:
- E.g. in a genealogical {Family, Person} data model,
for the many-to-many relation [Parent] <----> [Child]
MaxCard(Parent):MaxCard(Child) has the value 2:M :
[Parent]ɚ--------------M>[Child]